This is actually a question from an exam, but I believe it could help others troubleshooting a similar situation.

In a system, an e-mail needs to be sent to a certain mailbox. The following Java code, which is part of a larger system, was developed for that. Assume that "example.com" corresponds to a valid registered internet domain.

The execution of this code, within the testing environment of an application server, does NOT work as expected. The mailbox of the "example.com" server never receives the email, even tough all string values in the code are correctly attributed.

The output for the command "netstat -np TCP" in the application server during execution is shown bellow: